Over the past 1, 400 years, megaquakes in the Nankai Trough have occurred every 100 to 200 years, according to the president’s Headquarters for Earthquake Research Promotion.
The last one ever to be recorded occurred in 1946.
The possibility of a second quake occurring every year is growing by about 1 %, according to a member of the Earthquake Research Committee’s secretariat.” It’s been 79 years since the last quake,” an official told AFP.
Smaller islands off the principal coasts may be sucked into by a wave that is at least 30 meters high, according to authorities projections for 2012.
On the key islands of Honshu and Shikoku, densely populated areas may be hit by strong tides within a few minutes.
The Japan Meteorological Association ( JMA ) issued its first megaquake advisory last August in accordance with regulations put in place after the devastating 2011 tsunami and earthquake in Tohoku.
Following a magnitude 7.1 shock that left 15 people injured, the likelihood of a new key earthquake along the Nankai Trough was higher than normal.
After a month, the advice was lifted, but there were shortages of grain and other essentials as people restocked their crisis stores.
In 1707, all parts of the Nankai Trough ruptured at after, unleashing an disaster that remains the world’s second-most strong on history.
Two prominent Nankai megathrusts were followed by two strong earthquakes in 1854 and 1944, respectively, which likewise caused the most recent eruption of Mount Fuji.